2-DOF并联行程放大机构结构参数优化

Optimization design of structural parameters of 2-DOF parallel stroke amplification mechanism

为研制一种能实现快速行走、运动灵活性好的仿生四足机器人,对一种能够实现机构末端位置行程放大的2自由度并联机构进行运动性能分析与结构参数优化,并将优化结果应用到仿生四足机器人的腿部机构,研制出样机。首先,推导2自由度并联行程放大机构位置反解,建立机构的线速度雅克比矩阵,对机构的工作空间进行分析。其次,建立机构运动灵活性能评价指标,揭示主要结构参数对灵活性能指标的影响规律。然后,采用容限加权法确定一组合理的结构参数,使运动灵活性能指标达到最优。最后,根据优化的结构参数设计出仿生四足机器人腿部机构和整体的虚拟样机,并进行虚拟样机运动仿真。仿真结果表明:并联行程放大机构各驱动参数变化平稳,理论速度和仿真速度误差在±1.6×10-6m/s范围内,验证仿生四足机器人腿部机构设计方案和结构参数的合理性及理论推导的正确性,为该仿生四足机器人的进一步研究奠定了基础。

The objective of this study was to develop a bionic quadruped robot that can realize fast walking and good mobility.Motion performance analysis and optimization of structural parameters for a 2-DOF parallel mechanism that can realize end-position travel amplification of the mechanism were conducted.Optimization results were then applied to the leg mechanism of a bionic quadruped robot,and a prototype was constructed.First,an inverse solution of the 2-DOF parallel travel amplification mechanism was deduced,the linear velocity Jacobian matrix of the mechanism was established,and the workspace of the mechanism was analyzed.Second,an evaluation index of the flexible performance of the mechanism was established to reveal the influence law of the main structural parameters on the flexible performance index.Then,a set of reasonable structural parameters was determined using the tolerance weighting method to optimize the performance of the kinematic flexibility.Finally,based on the optimized structural parameters,the bionic quadruped robot leg mechanism and a virtual prototype were designed.Motion simulation of the virtual prototype was then conducted.The simulation results show that the driving parameters of the parallel stroke amplification mechanism changed smoothly,and the theoretical and simulation speed errors are within the range of±1.6×10-6m/s,which werified the rationality of the design scheme and the structural parameters of the bionic quadruped leg mechanism and the correctness of theoretical derivation.This study provides a foundation for further research on bionic quadruped robots.